Various release devices are utilized in archery to assist the archer in pulling a bow string to a fully drawn position and then releasing the bow string to fire an arrow. Many of these devices include mechanical grippers that engage the bow string directly, or that engage nock elements mounted on the bow string. Other devices use rope looped about the bow string as the release mechanism with or without a mechanical trigger. In release devices of the latter kind, the looped rope is often subject to a twisting action as the archer draws the bow string due to a cocking or turning action of the archer""s wrist. This kind of twist or torque applied to the release rope can result in reduced arrow speed and accuracy.
Conventional triggerless back tension rope releases are disclosed in U.S. Pat. Nos. 5,694,915 and 5,965,884. In release aids of this type, it is simply a slight movement of the archer""s arm and/or hand, after the arrow is fully drawn, that causes the release of the rope loop from the rope loop hook on the sear, and the concurrent release of the bow string.
It is known to provide a sensitivity adjustment feature that permits adjustment of a xe2x80x9cpawlxe2x80x9d member that engages the sear to thereby change the degree of movement of the archer""s hand required to release the arrow. Increased sensitivity, however, increases the potential for accidental premature firing and/or the possibility of injury to the archer as is or her arm snaps back toward the face.
This invention relates to a triggerless back tension rope release that provides additional freedom of movement during draw by incorporating a two-link release head assembly, each link (a forward link and an intermediate link) freely pivotable about respective pivots relative to each other and to the release handle. The sear, formed with a rope loop hook, is pivotably mounted on the forward link while the pawl is adjustably fixed for movement with the intermediate link. This arrangement allows the archer to draw the bow, with the handle portion of the release assuming various positions and angles throughout the draw cycle, relative to the release head assembly but without affecting the relationship between the pawl and the sear. A locking mechanism is provided that includes mutually perpendicular drive and locking rods that can be actuated through a lever in the handle portion to lock the intermediate link of the release head in any desired position, but leaving the forward link that supports the sear free to swivel relative to its respective pivot axis, but with its arcuate range limited by the position of the intermediate link. In this locked position, the handle, intermediate link and pawl will move together relative to the sear. The arrow can then be released by the conventional movement or flexing of the hand and/or wrist that causes the pawl to move to a position that releases the sear for movement that concurrently causes the rope loop to disengage from the sear hook and the arrow to fire, under the influence of tension in the bow string.
In a preferred arrangement, the xe2x80x9cpawlxe2x80x9d is formed to have a substantially triangular shape with radiused corners where the sides of the triangle meet the base. The sear edge is arranged to engage one of the sides of the triangle adjacent the base, and to be released as it passes across one of the radiused corners when the archer moves the release and the pawl sufficiently to allow the rear edge to clear the pawl. A pair of set screws are arranged to engage the two sides of the triangle, thus permitting very fine adjustments to the pawl vis-a-vis the sear. Since the pawl is pivotally mounted through a center portion thereof, the set screws engaging the side of the triangle work in opposed directions, i.e., tightening of one requires loosening of the other and vice versa.
The above described release head assembly and locking mechanism allows the archer to find the optimum draw position before locking the intermediate link, eliminating or at least significantly reducing any potential premature firing of the arrow.
It is another feature of the invention to fix the rope loop ends at a location on the forward link of the release head assembly that is closely adjacent and forward of the pivot pin of the sear, and more particularly, closely adjacent the rope loop hook on the sear. This arrangement insures that the release rope travels from its connection holes in the forward link in a straight line around the bow string and back to the sear hook, where the distance between the release rope lengths at the bow string is equal to or greater than the distance between the release rope lengths at the rope connection holes in the sear and the rope loop hook on the sear. In other words, the distance between the rope release lengths at the sear is substantially equal to or less than the diameter of the bow string. This insures that the bow string is maintained accurately in the exact same position of the release rope xe2x80x9ccradle,xe2x80x9d not allowing the bow string to slide or move to a varying positions, thereby maintaining a consistent amount of back tension travel to release the shot.
Thus, in accordance with one aspect, the invention relates to a triggerless back tension release for use with a bow string, the release comprising a handle portion with a post extending substantially perpendicularly away from the handle portion; a two-link release head assembly secured to a free end of the post remote from the handle portion, two-link release head including an intermediate link pivotably mounted on the post and a forward link pivotably mounted to the intermediate link; a rope loop having two free ends secured to the forward link; a sear pivotably secured to the forward link, the sear having a hook adapted to receive the rope loop; and a substantially triangularly shaped pawl fixed to the intermediate link and arranged to engage an edge of the sear and to release the sear upon relative movement between the pawl and the sear.
In another aspect, the invention relates to a triggerless back tension release for use with a bow string, the release comprising a handle portion with a post extending substantially perpendicularly away from the handle portion; a two-link release head assembly secured to a free end of the post remote from the handle portion, the two-link release head including an intermediate link pivotably mounted on the post and a forward link pivotably mounted to the intermediate link; a pawl mounted for pivotal movement in the intermediate link; the pawl comprising a substantially triangularly shaped component having a base and a pair of sides having truncated corner areas where the pair of sides join the base; a rope loop having two free ends secured to the forward link; a sear pivotably secured to the forward link, the sear having an edge at one end adapted to engage one of the truncated corner areas of the pawl, and a hook at an opposite end adapted to receive the rope loop; means for selectively locking the intermediate link relative to the post; and means for adapting and locking the pawl in a desired position relative to the rearward edge of the sear.
In still another aspect, the invention relates to a back tension release for use with a bowstring comprising a handle portion; a release head assembly secured to the handle portion; a sear pivotally mounted in the release head assembly, the sear having a hook at one end thereof and a sear edge at an opposite end thereof; a rope loop having two free ends secured to the release head assembly; and a substantially triangularly shaped pawl adjustably and pivotally mounted in the release head assembly with a corner edge of the pawl adapted for interaction with the sear edge; and adjustment screws in the intermediate link engageable with a side of the pawl adjacent the corner area to thereby enable selective adjustment of the pawl in two opposite directions relative to the sear edge.
In still another aspect, the invention relates to a pawl for use in a bowstring release head, the pawl having a substantially triangular shape including a pair of substantially identical sides connected at first ends to a base and at opposite ends to each other at an apex.